To be sold in Sydney at the Museum of Contemporary Art on 24 March 2013, following previews in London, New York and Melbourne.

"The Laverty Collection has evolved in a highly intuitive and personal way, shaped not by any pre-defined plan, but rather by a love of looking at art and a desire to be actively involved with it." Sue Cramer, 1998. Curator, Heide Museum of Modern Art, Melbourne, formerly of the Museum of Contemporary Art, Sydney.

The private collection of Sydney's Dr Colin and Mrs Elizabeth Laverty is one of Australia's greatest, featuring museum-quality works that have been sought by and lent to major galleries around the world, including the Musée du quai Branly in Paris, the State Hermitage Museum in St Petersburg, and the Museum Ludwig in Cologne.

The Laverty Collection auction is estimated to be worth between $4 million to $6 million, with about 300 lots to be sold, making it Australia's most valuable sale of a single collection of indigenous and non-indigenous contemporary Australian art. It marks the first time an auction of Australian contemporary art will be previewed internationally, in London and New York – a sign of the collection's importance.

Central to the Lavertys' collecting ethos is the belief that indigenous Australian art should be recognised as great contemporary art and viewed alongside that of non-indigenous Australian artists, rather than exhibited separately. The couple has long championed the idea that contemporary indigenous art more than holds its own in the broader story of Australian contemporary art.

Several of the couples' Whisson paintings are currently on loan to Sydney's Museum of Contemporary Art, for its Ken Whisson retrospective, and a number of early Papunya boards on loan to the Musée du quai Branly in Paris, as part of the National Gallery of Victoria's touring exhibition Tjukurrtjanu: Origins of Western Desert Art.

Bonhams' senior consultant Tim Klingender said: "During the last four decades, Dr Colin and Mrs Elizabeth Laverty have been among the most active collectors of Australian contemporary art (both indigenous and non-indigenous), continually pursuing works from contemporary art galleries and remote art centres, collecting artists in depth and setting artists' records when buying exceptional examples at auction.

"They have witnessed, and been part of, the flourishing trajectory of Australian Aboriginal art, at a time when this constantly evolving field has seen many prices grow exponentially, and new movements and art stars emerge.

"As Australia's only international auction house, Bonhams is in a unique position to take this exceptional collection of Australian contemporary art onto the world stage, holding previews at our galleries in London and New York in February and March, and in Melbourne in March, before the exhibition and auction at the Museum of Contemporary Art, Sydney."

Bonhams, founded in 1793, is one of the world's largest auctioneers of fine art and antiques. The present company was formed by the merger in November 2001 of Bonhams & Brooks and Phillips Son & Neale. In August 2002, the company acquired Butterfields, the principal firm of auctioneers on the West Coast of America. Today, Bonhams offers more sales than any of its rivals, through two major salerooms in London: New Bond Street and Knightsbridge; and a further three in the UK regions and Scotland. Sales are also held in San Francisco, Los Angeles, Carmel, New York and Connecticut in the USA; and Germany, France, Monaco, Hong Kong and Australia. Bonhams has a worldwide network of offices and regional representatives in 25 countries offering sales advice and valuation services in 60 specialist areas. For a full listing of upcoming sales, plus details of Bonhams specialist departments go to www.bonhams.com